Charge Transport in Weyl Semimetals

TL;DR

This paper investigates charge transport in Weyl semimetals, analyzing effects of Coulomb interactions and disorder, and provides theoretical predictions for conductivity behavior across different regimes, with relevance to experimental materials.

Contribution

It offers a comprehensive theoretical analysis of charge transport in Weyl semimetals considering interactions and disorder, including new calculations of conductivity in various regimes.

Findings

Conductivity in clean Weyl semimetals scales linearly with temperature.

Disorder induces a finite conductivity with a vanishing Drude width proportional to T^2.

Finite-frequency conductivity exhibits distinct behaviors depending on frequency relative to temperature.

Abstract

We study transport in three dimensional Weyl semimetals with N isotropic Weyl nodes in the presence of Coulomb interactions or disorder at temperature T. In the interacting clean limit, we determine the conductivity by solving a quantum Boltzmann equation within a `leading log' approximation and find it to be proportional to T, upto logarithmic factors arising from the flow of couplings. In the noninteracting disordered case, we compute the finite-frequency Kubo conductivity and show that it exhibits distinct behaviors for omega << T and omega >> T: in the former regime we recover the results of a previous analysis, of a finite conductivity and a Drude width that vanishes as NT^2; in the latter, we find a conductivity that vanishes linearly with omega whose leading contribution as T -> 0 is the same as that of the clean, non-interacting system sigma(omega, T=0) = N(e^2/12h)(|omega|/v_F). We compare our results to experimental data on Y2Ir2O7 and also comment on the possible relevance to recent transport data on Eu2Ir2O7.